1. Field of the Invention
The present invention is directed to a hearing aid of the type having a microphone for the reception of useful audio signals and for generating electrical signals corresponding to the audio signals, an amplifier for amplifying the electrical signals from the microphone and for supplying the amplified and processed signals to an electroacoustic transducer (earphone) that is designed for converting the amplified and processed signals into acoustic signals that can be supplied to the tympanic membrane of a hearing-impaired person.
2. Description of the Prior Art
Hearing aids should be as small as possible so that they can be inconspicuously worn. Small, miniature hearing aids are worn at the head behind the ear (BTE hearing aids) or in the concha (concha hearing aids) or in the auditory canal (ITE hearing aids). For manual operation, these hearing aids have, for example, an on/off switch, a switch for switching between "normal" operation using the microphone and operation in a telephone coil mode, and a volume control (potentiometer). Mechanical switches are also provided for modifying the transmission characteristic of the hearing aid.
More recent, programmable hearing aids have an electronic memory in which a number of transmission characteristics matched to various auditory/ambient situations can be stored. When, for example, the hearing aid wearer moves from a quiet environment into a noisy environment or vice versa, then he or she can match the hearing aid to the respective situation by actuating a switch or by selecting a specific, stored program. An example of such a hearing aid is disclosed in European 0 064 042.
Older hearing-impaired persons, in particular, often have difficulty in manipulating the miniature switches and therefore hearing aids having remote control by ultrasound (European Application 0 175 909), infrared or radio signals have been developed. An additional, larger control device with a transmitter is required for this purpose. Manual instruction signals must be transmitted to the hearing aid with a key field at the control device, and then must be received by the hearing aid and decoded in a special circuit and converted into the control signal corresponding to the desired function. Whereas the first-cited hearing aids have the disadvantage that manipulation of the operating elements becomes more difficult as the overall device becomes smaller is, hearing aids using a remote control unit have the disadvantage that always taking the larger control device along is required.